***Data Preparation***

The do files prefixed with "z" prepare data for subsequent analysis. They must be executed in sequential order, with each file preparing specific datasets as indicated by their names.

-Input Data 
   -aisrawdata.dta: Primary raw AIS (Automatic Identification System) vessel tracking data
   -dwt_clarkson.dta and Clarkson0.csv: Clarkson shipping database files with vessel characteristics
   Note: these confidential original data files are not included in the replication package.

-Output Data
   -ship_all_variables.dta: contains ship-specific information
   -ais_container_cleaned.dta: contains cleaned AIS data with irregularities removed.
   -ship_port_to_port.dta: contains final cleaned ship travel routes
   Note: all processed datasets are saved in the .\Repository\data_intermediate directory